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dc.contributor.authorLi, Xiangyu
dc.contributor.authorSvensson, Gunilla
dc.contributor.authorBrandenburg, Axel
dc.contributor.authorHaugen, Nils Erland L
dc.identifier.citationAtmospheric Chemistry and Physics. 2019, 19 (1), 639-648.nb_NO
dc.description.abstractCondensational growth of cloud droplets due to supersaturation fluctuations is investigated by solving the hydrodynamic and thermodynamic equations using direct numerical simulations (DNS) with droplets being modeled as Lagrangian particles. The supersaturation field is calculated directly by simulating the temperature and water vapor fields instead of being treated as a passive scalar. Thermodynamic feedbacks to the fields due to condensation are also included for completeness. We find that the width of droplet size distributions increases with time, which is contrary to the classical theory without supersaturation fluctuations, where condensational growth leads to progressively narrower size distributions. Nevertheless, in agreement with earlier Lagrangian stochastic models of the condensational growth, the standard deviation of the surface area of droplets increases as t1/2. Also, for the first time, we explicitly demonstrate that the time evolution of the size distribution is sensitive to the Reynolds number, but insensitive to the mean energy dissipation rate. This is shown to be due to the fact that temperature fluctuations and water vapor mixing ratio fluctuations increase with increasing Reynolds number; therefore the resulting supersaturation fluctuations are enhanced with increasing Reynolds number. Our simulations may explain the broadening of the size distribution in stratiform clouds qualitatively, where the mean updraft velocity is almost zero. © 2019 Author(s).nb_NO
dc.publisherEuropean Geosciences Unionnb_NO
dc.rightsNavngivelse 4.0 Internasjonal*
dc.titleCloud-droplet growth due to supersaturation fluctuations in stratiform cloudsnb_NO
dc.typeJournal articlenb_NO
dc.typePeer reviewednb_NO
dc.source.journalAtmospheric Chemistry and Physicsnb_NO
dc.relation.projectNorges forskningsråd: 231444nb_NO
dc.description.localcode© Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License.nb_NO
cristin.unitnameInstitutt for energi- og prosessteknikk

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Navngivelse 4.0 Internasjonal
Except where otherwise noted, this item's license is described as Navngivelse 4.0 Internasjonal